Firearm receiver mechanism with a roller detent pin for a telescopic breech-bolt

ABSTRACT

A receiver mechanism for a firearm which provides for the proper engagement of the locking lugs of the bolt with the locking abutments of the receiver. A roller-type pin acts as a detent to keep the bolt fully extended from the carrier when the bolt is open, so that the bolt lugs remain aligned with the locking abutments positioned in the fore-end of the receiver. On return of the carrier to the closed breech position, the bolt is allowed to close fully before starting to rotate, thus insuring precise engagement between the lugs and the locking abutments so proper locking can take place.

United States Patent Alday 1 Apr. 4, 1972 [54] FIREARM RECEIVER MECHANISM WITH A ROLLER DETENT PIN FOR A TELESCOPIC BREEClI-BOLT [72] lnventor: James M. Alday, Williamson, NY.

[73] Assignee: Remington Arms Company, Inc.,

Bridgeport, Conn.

[22] Filed: May 4, 1970 [21] Appl. No.: 34,145

[52] 11.8. CI ..42/l6 [51] Int. Cl. ..F41c 11/06, F4lc 11/00 [58] Field of Search ..42/l6; 89/188 [56] References Cited UNITED STATES PATENTS 2,960,917 11/1960 Lizza 42/16 3,101,648 8/1963 Walther ..89/l88 Primary Examiner-Benjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney-John H. Lewis, Jr. and Nicholas Skovran [57] ABSTRACT A receiver mechanism for a firearm which provides for the proper engagement of the locking lugs of the bolt with the locking abutments of the receiver. A roller-type pin acts as a detent to keep the bolt fully extended from the carrier when the bolt is open, so that the bolt lugs remain aligned with the 7 locking abutments positioned in the fore-end of the receiver. On return of the carrier to the closed breech position, the bolt is allowed to close fully before starting to rotate, thus insuring precise engagement between the lugs and the locking abutments so proper locking can take place.

1 Claim, 9 Drawing Figures PATENTEDAPR M972 3,653,140

sum 1 BF 3 fare/Mar" Mamas M A/d y PATENTEDAPR 4:972 3.653.140

sum 2 BF 3 [/7149/7 tar James M AVO g MHmd FIREARM RECEIVER MECHANISM WITH A ROLLER DETENT PIN FOR A TELESCOPIC BREECI-I-BOLT The invention relates to a receiver mechanism for a firearm which provides for the proper engagement of the locking lugs of the bolt with the locking abutments of the receiver, and more particularly to a receiver mechanism having a breech closing bolt with rotary motion to and from a locked position and a reciprocatory motion after unlocking to expose the breech of the barrel.

Receiver mechanisms of this type are not uncommon to the art, and one such design is shown by the patent issued to: Crittendon et al., U.S. Pat. No. 2,685,754, issued Aug. 10, 1954.

The present invention has many advantages over the previous systems. The present design is free of contoured slots in the receiver to align and guide the bolt. This makes for a stronger and less complicated receiver. The carrier is more positively located in the receiver. The bolt is completely free of the receiver and is located rotationally by the carrier and operating lever.

This, of course, necessitates a more precise and positive acting latching means, which the present system accomplishes by use of a roller detent pin. This detent is not dependent upon spring force and has a positive reciprocation which is dependent upon the carnming action of the receiver surfaces upon the detent during the reciprocation of the carrier mechanism within the receiver.

Less parts are required for the present system which provides easier assembly and reduction in cost. Also, there is a lesser tendency to misplace parts during disassembly.

The Crittendon et al. design depended on guiding at least one set of bolt lugs in a guide track of the receiver. This was to keep the bolt in the proper position as it reciprocated.

When the bolt was accelerated or decelerated, as especially when it was reversed in its movement, the cams tended to rotate the bolt. Thus, there was a tendency for the lugs to deform the track. In an attempt to correct this condition, a slotted finger latch mechanism was introduced.

This finger latch kept the bolt from moving relative to the carrier when the carrier reversed direction at the end of its excursion, and hence, avoided the tendency to deform the track at this point. With the positive latching of the bolt and carrier of the present system, it is possible to eliminate the guide track.

The present invention relies upon a simple roller detent pin which keeps the bolt fully extended from the carrier when the bolt is open, wherein the lugs are properly aligned with the locking abutments. The roller detent pin rests in a hole of the carrier and may extend partially within or without the carrier wall, depending upon the carrier position within the receiver. Its travel is limited towards the outer carrier surface by its contact with the receiver wall, and to the interior of the carrier by its contact with the bolt.

There is a recess milled into the receiver so that the roller detent pin can extend outside of the carrier, which allows the carrier to telescope over the bolt, providing rotation of the bolt by way of the carnming slots and carnming pin arrangement.

As the carrier is further withdrawn in the receiver, the roller detent pin rides out of the receiver recess and is forced into the interior of the carrier by the receiver wall to engage the bolt from passing back into the carrier. This detent action preserves the proper rotational alignment of the bolt lugs with the receiver abutments when the bolt is in the open position.

It is an object of this invention to provide an improved bolt latching system for the receiver of a firearm.

It is another object of this invention to provide a bolt latching system for the receiver of a firearm which is more positive acting.

It is a further object of this invention to provide a latching system for a firearm receiver which has fewer parts than present systems.

It is still another object of the invention to provide a latching system for the receiver of a firearm wherein the carrier is more positively located in the receiver than prior systems.

It is but a further object of this invention to provide a latching system for the receiver of a fireann wherein the bolt is completely free of the receiver so that the bolt has to be completely located rotationally by the carrier and latch in order to properly align with the locking abutments.

These and other objects of the invention will become apparent and will be better understood with reference to the following detailed description taken in conjunction with the drawings in which:

FIG. 1 is an exploded view of the various parts of the invention;

FIGS. 2 through 4 are isometric views of the carrier assembly in various stages of operation within the receiver wherein:

FIG. 2 shows the bolt in a closed and locked position;

FIG. 3 shows the bolt in a closed and unlocked position; and

FIG. 4 shows the bolt in an open position;

FIG. 5 is a cutaway perspective view of the carrier assembly depicting the carnming slot mechanism;

FIG. 6 is a cutaway perspective view of the carrier assembly depicting the roller detent pin engaging the necked body portion of the bolt;

FIGS. 7 through 9 are sectional top views of the carrier assembly in its various stages of operation within the receiver corresponding to FIGS. 2 through 4, respectively, wherein:

FIG. 7 corresponds to the top view of the carrier assembly of FIG. 2 when the bolt is in a closed and locked position;

FIG. 8 corresponds to the top view of the carrier assembly of FIG. 3 when the bolt is in a closed and unlocked position; and

FIG. 9 corresponds to the top view of the carrier assembly of FIG. 4 when the bolt is in an open position.

Generally speaking, the invention is for a breech bolt locking means for the receiver of a firearm. The bolt has at least one locking lug to marry with at least one locking abutment disposed in the receiver. A carrier is provided for the breech bolt. The carrier is reciprocal in the receiver from a closed bolt position to an open bolt position. Cam means interengage between the carrier and the bolt wherein reciprocation of the carrier produces both rotation and reciprocation of the breech bolt. The carrier has an aperture communicating between that portion of the carrier supporting the breech bolt and an exterior portion thereof which is in substantial engagement with a wall of the receiver. A roller detent pin is received in a cylindrically profiled aperture and is movable therein between a first position extending beyond the exterior of the carrier and not substantially extending into that portion of the carrier in which the breech bolt is received, and a second position in which the roller detent pin does not extend substantially beyond the exterior of the carrier and does extend substantially into that portion of the carrier in which the breech bolt is received. The breech bolt has an abutment engageable by said roller detent pin when said breech bolt is in an unlocked position and the roller detent pin is in said second position to restrain said bolt against movement relative to the carrier. The receiver wall has a rectangular slot to receive said roller detent pin as the bolt approaches its closed position, to permit relative motion between said carrier and said bolt, and consequently move said bolt lug into and out of locking engagement with said locking abutment.

Now referring to FIG. 1, an exploded view is depicted of the various parts of the mechanism. A carrier 4 is shown housing a breech bolt 3. The breech bolt has a bolt head 11 which has locking lugs 12 on the periphery thereof. The lugs 12 engage with the locking abutments 22 which are located in the interior of the nose piece 23 of the barrel extension 6. (See FIGS. 2 through 4). The nose piece fits into the interior of the receiver 2 at the fore-end 13. The extension 6 has a hole I8 through which the cylindrical projection 28 passes. The extension is made to fit flush with surface 26 of the receiver.

Although the preferred embodiment of this invention disposes the locking abutments within the receiver by way of extension member 6, it is possible that these abutments may be made an integral part of the receiver 2 or part of the rear section of the barrel of the gun if so desired, without departing from the inventive concept or smooth operation of locking.

The breech bolt 3 is shown in its extended position with respect to the carrier 4. In this position, the camming slot 14 is exposed to view. An excellent view of the camming mechanism is shown in FIG. 5. The camming slot 14 runs completely through the bolt 3. The operating lever l is com posed of a finger-piece 8 and a tubular protuberance 7 that runs through the carrier hole 17, and through slot 14 of the bolt. Hole 17 runs completely through the carrier so that the protuberance 7 extends from one side of the carrier to the other side thereof (see FIG. 2). A locking pin 5 is inserted through the bottom of the carrier and reaches to the exit hole 25 of the carrier as shown in FIG. 2. This pin also passes through hole 15 in the tubular protuberance 7. The purpose of pin 5 is to lock the lever 1 against rotation with respect to the carrier as well as preventing its removal therefrom. The tubular protuberance 7 acts as a camming member within slot 14 of the bolt. The retraction of the lever will reciprocally force the carrier to move within the receiver and simultaneously cam the bolt into rotating clear of the locking abutments 22, as will be further explained hereinafter.

The operating lever 1 has its finger piece 8 extending through the port window 10 of the receiver 2. The slot 20 is provided for the complete retraction of the lever.

The receiver 2 has an interior wall 30. A rectangular slot 19 is in the side of the wall. A roller-type detent pin 9 rests within the slot 19 when the bolt is in the closed breech position as shown in FIGS.2 and 3.

The roller detent pin 9 also rests within hole 29 of the carrier. Hole 29 extends from the peripheral surface of the carrier into the interior hollow surface provided for the bolt, and has a cylindrical profile to accomodate the roller detent pin.

OPERATION OF THE MECHANISM The workings of the device can best be understood with reference to FIGS. 2 through 4, and FIGS. 7 through 9.

FIGS. 2 through 4 are isometric cutaway views of the carrier assembly in various operating locations within the receiver, and FIGS. 7 through 9 are the respective views of FIGS. 2, 3, and 4 as shown in a sectional top view.

Referring to FIGS. 2 and 7, the carrier assembly is shown with the breech bolt in the closed and locked position. The bolt head 11 is locked within the nose piece 23 of the barrel extension 6 by means of its locking lugs 12 which are in rotational locking engagement with locking abutments 22. In this position the bolt head 11 is flush against the front face 21 of the carrier 4.

The roller detent pin 9 rests in the forward end of rectangular slot 19 and extends into the cylindrically profiled hole 29 of the carrier only so far as not to go beyond the interior wall 49 of the carrier. This position of the roller detent pin can best be seen with reference to the top view (FIG. 7).

The bolt is in the unlocked and closed position in FIGS. 3 and 8. As the lever l is reciprocally retracted as shown by arrow 31, the carrier 4 is withdrawn in the receiver, causing the bolt 3 to cam to an unlocked position as depicted by arrow 32.

The camming action can be better understood by observing FIG. 5. As the lever is retracted rearward, the tubular element 7 causes the carrier to move rearward because it is fixed within hole 17 of the carrier. The bolt, however, is forced to rotate as tubular element 7 moves within the camming slot 14 of the bolt.

It should be observed that the bolt head 11 is now extended from the carrier face 21.

The roller detent pin 9 is now resting at the rearward end of rectangular slot 19, and does not extend beyond the interior wall 49 of the carrier as it partially rests within hole 29 of the carrier (see FIG. 8).

Now referring to FIGS. 4 and 9, the bolt is shown in the unlockedand open position. The lever 1 has been retracted still further rearward as depicted by arrow 41 The tubular element 7 has already cammed the bolt to its unlocked position. Therefore, further retraction of the lever causes the bolt to retract in concert with the carrier.

The roller detent pin 9 is caused to ride out of slot 19, wherein it is now caused to rest upon the interior receiver wall 30. When the roller detent pin is in this position, it is forced into the interior cavity of the carrier by the receiver wall. The roller detent pin now extends beyond the interior wall 49 of the carrier. The roller detent pin 9 now acts in its role as a detent by engaging the necked portion (abutment) 39 of the bolt. This engagement prevents the bolt from moving reciprocally within the carrier. The prevention of reciprocation of the bolt consequently freezes the bolt in its extended position relative to the carrier, and thus prevents the bolt from rotating to its locked position while it is opened.

When the lever is returned towards the closed breech position, the roller detent pin is made to once again ride within the rectangular slot 19, thus releasing the bolt for rotation.

Thus, a precise and positive locking action is accorded the bolt head as it is reciprocated back and forth between its closed and open positions.

Many modifications and variations of this invention will be apparent to those skilled in the art.

The abutment (necked portion) 39 of the bolt 3 may take the form of a recess, sharp-angled bend, or tab, in order to engage or receive the detent.

Such aforementioned modifications are considered to be within the purview and scope of the invention as depicted by the appended claims.

What is claimed is:

l. A firearm receiver mechanism comprising:

a receiver having a hollow portion characterized by an elongated interior wall, said wall containing a rectangular slot extending for a limited distance in prolongation of said receiver wall;

at least one locking abutment disposed within the fore-end of the receiver;

a breech bolt having an abutment with a curved surface for accommodating the side profile of a cylindrical roller detent pin, and at least one locking lug for engagement with one of the locking abutments;

a hollow non-rotary breech bolt carrier reciprocallydisposed within said receiver and connected to said breech bolt, said breech bolt reciprocally and rotatably disposed within the carrier hollow which is defined by an interior wall of said carrier, said carrier having an exterior wall containing a hole having a cylindrical profile for receiving a roller detent pin, said hole extending through said exterior wall into said interior wall;

cam means interengaging between the carrier and the breech bolt for producing both rotation and reciprocation of the bolt when the carrier is reciprocated within the receiver;

means for retracting the carrier and bolt combination from a closed locked bolt position to an open unlocked bolt position;

a roller detent pin for prolongated movement within, and rolling engagement with, the receiver slot and interior receiver wall, said roller detent pin partially resting within said receiver slot and partially contained within said carrier hole when the bolt is in the closed locked bolt position; said roller detent pin being forced out of said slot into contact with the interior wall of said receiver when the carrier and bolt are retracted to the open unlocked bolt position, wherein said roller detent pin is forced by said receiver wall into extending further into said carrier hole and beyond the interior wall of said carrier to engage the bolt abutment and prevent the bolt from reciprocating within the carrier and rotating to its locked position while retracted. 

1. A firearm receiver mechanism comprising: a receiver having a hollow portion characterized by an elongated interior wall, said wall containing a rectangular slot extending for a limited distance in prolongation of said receiver wall; at least one locking abutment disposed within the fore-end of the receiver; a breech bolt having an abutment with a curved surface for accommodating the side profile of a cylindrical roller detent pin, and at least one locking lug for engagement with one of the locking abutments; a hollow non-rotary breech bolt carrier reciprocally disposed within said receiver and connected to said breech bolt, said breech bolt reciprocally and rotatably disposed within the carrier hollow which is defined by an interior wall of said carrier, said carrier having an exterior wall containing a hole having a cylindrical profile for receiving a roller detent pin, said hole extending through said exterior wall into said interior wall; cam means interengaging between the carrier and the breech bolt for producing both rotation and reciprocation of the bolt when the carrier is reciprocated within the receiver; means for retracting the carrier and bolt combination from a closed locked bolt position to an open unlocked bolt position; a roller detent pin for prolongated movement within, and rolling engagement with, the receiver slot and interior receiver wall, said roller detent pin partially resting within said receiver slot and partially contained within said carrier hole when the bolt is in the closed locked bolt position; said roller detent pin being forced out of said slot into contact with the interior wall of said receiver when the carrier and bolt are retracted to the open unlocked bolt position, wherein said roller detent pin is forced by said receiver wall into extending further into said carrier hole and beyond the interior wall of said carrier to engage the bolt abutment and prevent the bolt from reciprocating within the carrier and rotating to its locked position while retracted. 